polynomial_kernel.hpp

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#ifndef MLPACK_CORE_KERNELS_POLYNOMIAL_KERNEL_HPP
#define MLPACK_CORE_KERNELS_POLYNOMIAL_KERNEL_HPP

#include <mlpack/prereqs.hpp>

namespace mlpack {
namespace kernel {

class PolynomialKernel
{
 public:
  PolynomialKernel(const double degree = 2.0, const double offset = 0.0) :
      degree(degree),
      offset(offset)
  { }

  template<typename VecTypeA, typename VecTypeB>
  double Evaluate(const VecTypeA& a, const VecTypeB& b) const
  {
    return pow((arma::dot(a, b) + offset), degree);
  }

  const double& Degree() const { return degree; }
  double& Degree() { return degree; }

  const double& Offset() const { return offset; }
  double& Offset() { return offset; }

  template<typename Archive>
  void serialize(Archive& ar, const uint32_t /* version */)
  {
    ar(CEREAL_NVP(degree));
    ar(CEREAL_NVP(offset));
  }

 private:
  double degree;
  double offset;
};

} // namespace kernel
} // namespace mlpack

#endif